You have no idea what it takes to gain citizenship! First, it is offered to extremely few. Requirements are ridiculously rigid. Luis would never qualify to even put his name on the first of many forms needed. The paperwork is voluminous. The filing fees and other expenses are hefty. One simple error and you start over and pay more filing fees. Even for well educated, “acceptable” applicants, the process can be daunting. But, back to basics and your ignorant comment, Luis and people like him, raised in the USA, often not realizing until adulthood that they are not legal Americans, have no recourse for citizenship. If they even show up at an INS (now Homeland Security) office to inquire about citizenship, they will likely be arrested and deported.
We have a friend who qualified to apply for a permanent resident card and later, citizenship. In spite of meeting the necessary requirements, both processes took more than 10 years, thousands of dollars, and 12 trips to the closest INS office two hours away, difficult to do when you work 3 jobs at minimum wage for 60+ hours a week.
Educate yourself before commenting on subjects you know nothing about.